Split-cycle internal combustion engines are known in the art albeit in their early stages of development and realization. For example, WO03/008785 assigned to Scuderi Group is concerned with offsets to optimize the compression stroke in a split-cycle engine. The Scuderi Group has a range applications and patents in this field and although it is mentioned that the principle applies to CI engines, none of their applications and patents address some specific issues associated with split-cycle CI engines. The current disclosure is aimed at addressing at least some of the shortcomings of the prior art.